Process Insights

Machine Automation Improves Productivity at Cincinnati Mine

Automated Production Machining Improves Machining Efficiency of Steel Forging Component

Coal mining is as relevant today as it is historic, providing a large percentage of the world with the fuel to generate electricity for modern conveniences. Due to coal’s significance in the energy market, many manufacturers working with the coal mining industry were unhindered by the recent economic troubles cascading around them.

“Business has been good over the last several years, and forecasts continue to look strong, but that doesn't mean we should sit still,” says Tim Jent, production supervisor at Cincinnati Mine Machinery. “The marketplace is full of stiff global competition, and the growth we’re seeing only presents new opportunities to expand our shares and improve our business performance and profitability.”

Cincinnati Mine Machinery has a robust history in the United States as a fourth-generation, family-owned company founded in 1924. It produces a variety of OEM and replacement components for several of the world’s largest mining equipment manufacturers, with an emphasis on conveyor systems. While facing increasing sales activity and limited production capacity in 2008, Cincinnati Mine Machinery began researching new machine automation technologies that would enable it to improve throughput and maintain higher consistency in its part quality. The company’s solution was the installation of a Makino Machining Complex (MMC2) with 24 pallets and two a71 horizontal CNC machines.

“Our five previous milling machines from 1995 weren’t cutting it anymore, causing us daily headaches with regard to reliability, inconsistency and productivity. We had to do something,” says Jent. “The installation of the new Makino machining cell enabled us to replace five CNC machines with two, while doubling our production machining capacity, redeploying labor and improving our overall quality and flexibility. And rather than focusing on batch orders, we’re now able to work on quicker, smaller work quantities that reduce our in-house inventory and allow us to change orders on the fly.”

Enduring the Coal Mines

While advancements in technology have made coal mines safer for miners, the environment still causes harsh wear and tear on mining equipment. Chain assemblies, like those made by Cincinnati Mine Machinery, face daily abuse from mechanical interferences and conveying large volumes of coal and rock. The chain pins and block assemblies wear and fatigue, chains begin to elongate and sprockets wear, reaching a point where they no longer engage correctly. As a result, the life span of these assemblies typically lasts between 12 and 14 months.

Cincinnati Mine Machinery addresses the need for OEM and replacement components by producing many unique conveyor chain assemblies of diverse size, strength and duty cycle requirements.

“Tough, consistent quality is essential to our chain assemblies,” says Jent. “As such, all chains are manufactured and assembled in-house to ensure proper fitting and alignment. The materials we work with are typically heat-treated steel forgings ranging between 40 and 50 Hrc to endure the severe duty these products will see in the field. To machine these parts quickly, accurately and repeatably, we needed CNC machines like the a71s that offer a strong, rigid design and powerful spindle performance.”

Preparing For Machine Automation

The investment in automated production machining capabilities was a new direction for Cincinnati Mine Machinery, and the single largest capital investment in its history.

“Machine automation, at this level, was a giant leap for our company, but one that needed to happen in order to meet our rising demand for increased capacity,” says Jent. “Makino—understanding our limited exposure to automation—offered us a tremendous level of support during implementation. Within three weeks, their engineering services were producing initial runs of the key steel forging at their facility. Together, we fine-tuned the cell and its accessories for optimal quality, capacity and cost.”

After approximately three months, Cincinnati Mine Machinery’s customized automation solution was installed in its facility.

“The completed solution addresses all of our needs from top to bottom, regarding speed, reliability and accuracy,” says Randy Morris, Cincinnati Mine Machinery’s manager of engineering. “Prior to this, hardmilling processes were punishing our hydraulic fixtures, causing frequent fluid leakage and reduced rigidity. The new custom mechanical fixture designs we developed remove these issues, providing improved strength, rigidity and reliability even in our toughest applications.”

A Change in Production Machining Strategy

Cincinnati Mine Machinery’s initial production runs involved a single chain assembly that made up 65 percent of its conveyor business. Since then, the company has added several part families to the cell.

“Prior to the integration of the MMC2, our production philosophy focused on large batches,” says Jent. “The variety of parts produced on the cell eventually became so great that we decided to take advantage of our increased flexibility and move to a kanban system, where we can schedule part orders on the fl y.”

The Makino cell’s MAS-A5 control system enables the company to instantaneously coordinate production machining schedules for increased flexibility. When high-priority orders come through, the operator is able to suspend current processes and call up the new job in just 30 seconds. Once completed, the suspended job can resume without any concerns related to positioning inaccuracies.

The improved production planning capabilities provide Cincinnati Mine Machinery with the ability to continuously alternate batches. Whereas operators were once required to load and unload parts in less than 15 minutes on some large orders, they can now juggle batches of longer and shorter run times to afford additional changeover time between jobs.

“Even with over 25 different part varieties, we’re still running more efficiently than ever, producing about 20,000 parts each month while running two shifts,” says Morris. “The cell’s scheduling software and unattended reliability have reduced our overall cycle times by 70 percent compared to previous processes and have enabled us to run parts over nights and some weekends when our orders are even higher. To sum it up, we’re running more parts with better quality, faster than at any other point in the company’s history.”

Improving Consistency, Tool Life and Flexibility

By producing and assembling full conveyor chains in-house, Cincinnati Mine Machinery understands the importance of reliability, repeatability and dependability in its machining investments. While previous machines required a high level of operator activity that resulted in some human error, the Makino cell has removed a large percentage of manual involvement, providing the company with significant improvements in part quality, consistency and tool life.

“Even if only one part is made incorrectly, it can throw off the entire assembly alignment, potentially causing difficulty in the field,” says Jent. “This means the pitch, squareness and everything else must be consistent throughout the assembly.”

“The a71 cell’s tool pre-setter, part probing and BTSOMA [broken tool sensor outside of machining area] have enabled us to produce parts day in and day out that look the same as our first run,” says Morris. “We no longer run into issues of operators loading tools, inserting fixtures or programming macros uniquely. Everything is preset one time within the cell’s controller and monitored for accuracy with each new load. If any measurements deviate from the preprogrammed specifications, the control will signal the machine to postpone production or change tooling.”

Cincinnati Mine Machinery also reports that the programming, monitoring and probing support within the MMC2 and a71 CNC machines have contributed to extended tool life and reduced tool breakage, decreasing its overall tool spend by 30 percent despite new investments in more expensive, high-efficiency tooling solutions. According to Morris, “Not one tool, fixture or holder was transferred over from the old machining process. If anything, one would assume that our tooling expenditure would have increased, but that’s far from the truth. They actually declined!”

The switch to automation has influenced a change in the company’s overall production machining philosophy, closely analyzing the trade-off between tooling expense and productivity. The flexibility of the a71 CNC machines provide Cincinnati Mine Machinery with a wider selection of new tooling that previously couldn’t be used on its older machines. As such, the company is continually evaluating new tooling options in order to determine whether increases in productivity can offset the cost of new tools.

“By changing our tooling approach, we’re now able to share tools between jobs, freeing up space in the tool changer for more applications and optimizing our tool usage,” says Morris. “We’re also taking advantage of the a71 CNC machines' faster feed rates, using shorter tools with more aggressive cutting for higher metal-removal rates. In total, parts are now running at least two to three times faster, even with more tools touching each part.”

Remaining Competitive

Cincinnati Mine Machinery found its solution for improved throughput and part consistency in its Makino MMC2 machining cell, but it has no intent to slow its advancements. The company is currently working on tackling an automated solution for material handling to and from the cell for improved efficiency in fixture loading and finished part delivery to other departments.

“Machine automation was a clear next step for our business, and there are still plenty of opportunities to expand on these capabilities,” says Jent. “One of the best features of the MMC2 is its flexibility for expansion, and we’ll be sure to take advantage of it. At our current rate of growth, we could see potential additions to the cell within the next few years.

“Investing in machine automation produced a clear and fast return on investment. Nearly every aspect of our production has changed for the positive-increased productivity, improved efficiency, better quality and reduced tool expense. The takeaway is clear: Competing in today’s marketplace requires reliable, repeatable, dependable automated production capabilities.”

Cincinnati Mine Machinery
Cincinnati, Ohio
(513) 522-7777

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